Apparatus for molding concrete pipe



J1me 1953 H. x. ESCHENBRENNER ,818

APPARATUS FOR MOLDING CONCRETE PIPE Filed Sept. 4, 1948 A 2 Sheets-Sheet l wyw cwrX

A June 16, 1953 x, sc-HE 2,641,818 APPARATUS FOR MOLDING CONCRETE PIPE Filed Sept. 4, 1948 2 Sheets-Sheet 2 RfL. 50

flcwrXgfckanrenner Patented June 16, I 1953 UNITED STATES PATENT OFFICE r 2,641,818 I I APPARATUS FOR MOLDING CONCRETE PIPE Hector x. Eschenbrenner, Columbus, Ohio Application September 4, 1948, Serial No. 47,766

- 4 Claims.

oluble packer head. In such apparatus, the

shaft and its associated head are raised vertically in measured or predetermined increments of movement while a cementitious mix is introduced into the mold, the packer head engaging themix to compact the latter and control its density. By the use of such standard apparatus for producing pipe, the density'of the pack depends almost entirely upon coordinating the speed of elevation of the packer and the amount of mix which is fed to the vertical mold. The amount of mix introduced into the mold is usual- 1y entirely dependent upon the skill and judgment of the machine operator, and this condition results quite commonly in a variable density in the walls of the finished concrete pipe, a property that is highly undesirable in that it directly affects the water absorption rate and mechanical strength of the finished product.

It is another object of the invention to providea machine for producing concrete pipe in which the walls of the pipe may be formed readily to possess a uniform density throughout the entire length of the pipe.

It is another object of the invention to provide apparatus for making concrete pipe which may be readily adjusted to obtain desired density I factors in the formed pipe.

A further object is to provide apparatusinvolving a stationary cylindrical outer mold having arranged in its vertical longitudinal axis a rotary packer head assembly consisting of a relatively short core having fixed to the sides thereof segmental packer shoes, the packer head assembly being so mounted as to yield vertically against a fixed resistance as the height of an associated pipe increases during its process of manufacture. I

A still further object of the invention is to provide inv a forming machine for making concretepipe a rotary core section having ar-cuate packer shoes on its outer surface and mounted, for rotation within a vertical mold, and wherein,

fluid pressure-actuated means are provided for 2 applying a constantly downwardly directed force to the core section and its packer shoes, which force, is adapted to be overcome as the height of the pipe undergoing formation increases in the mold, the resistance offered by fluid pressure to the raising of the core section being such as to produce uniform compaction of the cementitious mix introduced into the mold, the packer shoes floating on the upper end of the pipe during the formation of the latter and rotation of the core section.

'It is another object of the invention to provide a concrete pipe making machinevin which the density of the cementitious mix employed in forming such pipe is automatically controlled and is not subject to variation of the kind resulting from manually performed operations.

Another object is to provide means for producing concrete pipe of any desired density and moisture content and for varyingsuch density or moisture content by increasing or decreasing resistance offered by a .rotary packer head to ascent when the packer head is in contact with a pipe body undergoing formation.

For a further understanding of the invention, including additional objects, advantages and constructional details, reference is to be had to the following description and the accompanying drawings, wherein:

Fig. 1 is a vertical sectional view, partly in side elevation, of apparatus employed by the present invention in the formation of concrete P p Fig. 2 is a similar view on an enlarged scale disclosing the shaft, core and packer shoe construction of the apparatus comprising the present invention;

Fig. 3 is a horizontal sectional view taken. on

the plane indicated by the line 3-3 of Fig. 2;

Fig. 4 is a circuit diagram of the hydraulic system associated with the present pipe forming tional view taken through a modified form of perforate mold form.

The apparatus shown specifically in the drawing to exemplify the present invention comprises a tubular vertically positioned outer mold l0. Preferably, the mold is of sheet metal construction and composed of two halves, the latter being hinged together as at II and having their opposed meeting edges secured together by latch devices 12, so that the mold may be opened to remove molded pipe therefrom. In a preferred form of my invention, the mold walls are of imperforate formation, while in a modified form, as shown in Fig. 7, the mold walls may be perforated as at l3, whereby to facilitate the discharge of excess moisture from a cementitious mix introduced into the mold.

The mold It when in use is adapted to be positioned in an upright manner with its lower end suitably supported in the confines of a positioning ring I l carried by a stationary base l5, the latter being formed with a pit Hi disposed in registration with the mold 19. The mold may be of any suitable length or height, and is adapted to have its upper end removably received in a top ring member ll carried by the under party of a platform 18 in which an opening Isis formed in registration with the open upper end of the mold l0.

Movable vertically in the longitudinal axis. of the mold is a core shaft. 29', the lower end of the shaft being formed with or having aflixed thereto a cylindrical core 2|. The outside diameter of this core is. less than the inside diameter of the mold 10, so that when the core is positioned within the mold an annular space is provided between its outer Wall surfaces and the inner wall surfaces of the mold to receive the cementitious mix from which tubular members, such as pipe, are formed.

Apparatus, not shown, for producing such a cementitious mix may be arranged on the platform 18, and a discharge spout 22 employed for conducting the mix to the open upper 'end of the mold ll} into which the is introduced for deposit on the bottom ringstructure 14- and in the annular space provided between the inner Walls of the mold is and the outer walls of the core 2|.

Toward its upper end, the outer part of the core 2! is provided witharcuate orsegmental packer shoes 23 which contact the upper surfaces of the mix introduced into the mold. A uniform downward pressure is at all times applied to the core during active manufacture of concrete pipe, whereby to produce pipe in which the wall structurethereof possesses uniform density and desired water absorption characteristics.

The packer shoes float, as it were, on the upper edge of the pipe wallas the same is built up in the mold, and it willbe' noted that the rate of introduction of fresh mix into the mold does. not.

affect the density of the formed pipe. If the amount of the mix should be in excess of that actually required atv any given period of operation, the excess mix merely remains. above the packer shoes until the wall structure of the. pipe reaches that degree of compaction and density necessary to elevate the packer (the core 2| and its shoes 23) against a fixed load thereon. Therefore, the apparatus is in large part automatically operative and independent of variable factors often present in manufacture as a result of varied skills of the machine operatives. While a core section of relatively short length has been shown, it will be understood that the length of said core section will be such as to properly and smoothly form the interior of a pipe and before the core uncovers the interior-surface of the pipe, the latter will possess such wall stability as to sustain compaction forces independently of the core. During initial stages in the manufacture of pipe, the core occupies the pit 16, at least in part.

To rotate the shaft 20 and its associated core 2|, any suitable mechanism may be employed. In the apparatus illustrated, use is made of an electric motor 24 supported by a stationary frame 25. Its armature shaft is provided with a pinion 26, the teeth of which mesh with those of a horizontally disposed gear wheel 21, the hub of the gear wheel being formed with a keyway for the reception of a vertically disposed and longitudinally extending key 28 provided on the shaft 20. Thus, as the shaft and core move vertically, continuous rotary movement will be imparted thereto through the operation of the motor and the gearing disclosed. I

Many different devices may be employed for applying a uniform load or downward thrust to the shaft 20. and its associated core 21. In the apparatus. illustrated, I have shown fluid-actuated means for accomplishing the application of such a load which offers a fixed resistance to up- Ward travel of the core in the mold Ill. Such fluid-actuated mechanism is used because of its inherent simplicity and ease of control, although.

other equivalent means may be utilized without departing from the spirit of the invention.

In this instance, the upper end of the shaft 20 is carried in a swivel-type coupling 29. provided with an antifriction thrust bearing, by means of which the shaft 29 maybe conveniently rotated by the motor 24 whil downward pressure isbeing applied to the upper end of said shaft through the coupling 25%. The outer relatively stationary part of the coupling reconnected with the lower end of a rod 30 which-is mounted for reciprocation in a packed bearing provided in the lower end of a stationary cylinder 34-, the latter being suitably supported above the motor 24;. The upper end of the rod 30 is joined witha piston 32 which is slidably actuated by fluid pressure forverticalmovement within the cylinder.

To control the application of fluid pressure to the upper side of the piston 32-, use may be made of a liquid reservoir 33' into which extends apipe 3 leading to the inlet side of a motor driven pump 35". Extending from the outlet of the pump 35 is a pipe 36 which leads to a T-fitting 31-, a shunt pipe line 38 containing abiased pressure reliefvalve fie-being employed to connect the inlet and outlet pipes 34 and 36. of the pump and toprevent overloading of the system joined withthe outlet side of the pump.

Leading from the fitting 3-1 is a pipe line 40 which extends to atwo-position three-way valve 4 I. In thisvalve, there is arranged a rotaryplug 42 having a transverse port 43. This port may be registered with the discharge end of the pipe line 40. and with thefluid inlet 44' provided in the upper end of the cylinder 3|, thus admitting the fluid underpredetermined pressure into the cylinder for applying pressure to. the upper. side of therethrough which is adapted tov register with. the port 43 and the-line 45. of the valve. 4|. when.

plug 42, thence through theline 45 to the relief' valve46. The passage 41 of the relief valve contains a valve seat 48 which is normally closed by the head of a valve member 49 having a stem v50. Surrounding this stem is a spring .bymeans of which the valve member ismaintained in engagement with the seat 48. By the exteriorly located threaded means 52, the compression of the spring 5| may be varied. to regulate its re-,

sponse to different fluid pressures. Thus, as the piston 32 moves upwardly in the cylinder 3|, fluid is displaced from said cylinder, traveling through the valve 4| and the pressure-relief valve 46 while maintaining a constant fluid pressure on the upper end of the piston which is subject toregulation by varying the compression of the spring 5l'.

During upward travel of the pistonin such cylinder, the fluid discharge through the relief valve 46 enters a return pipe 53 which leads back to the reservoir or tank 33. From the pipe 53', a branch line 54 extends .to a two-position threeway valve 55, the latter having a rotatable plug 56 formed with a port 5! which is arranged to align with openings 58 and 59 provided in the casing of the valve 55. When the port fills in registration with the openings 58 and 59, fluid may be drawn from the return pipe 53 and advanced through a pipe line 60 into the under side of the cylinder 3| below the piston therein, thus drawing fluid into said cylinder as it is being expelled from the top thereof.

If it is desired to raise the shaft 3!] and its core 2 I, the valve 55 is positioned so that the port 51 of the plug 56 thereof registers with the opening 58 and with an opening 6| with which is 'joined one end of a branched pipe line 62 leading to the fitting 31 on the discharge side of the pump. By this construction, the packer head assembly of the pipe-forming apparatus may, at the will of the operator, be raised or lowered and also a desired fluid pressure or loading may be applied to the packer head assembly to resist its upward travel during a pipe-forming operation.

In view of the foregoing, it is believed that the construction and operation of the apparatus imparting adjustable and yieldable resistance to' forming mix; a shaft connected with and extend ing longitudinally outwardly from said core; means engaging said shaft for imparting axial rotation to said'shaft and to said core, said lastnamed means permitting of vertical movement of said shaft during rotation thereof; a packer shoe carried by and extending radially outwardly from said corefor engagement with the upper surface of a mix introduced within said chamber, said packer shoe being arranged on said core to press downwardly upon the upper surface of a mix introduced within said chamber upon rotation of said core to compact such mix within said chamber; and fluid'pressure-responsive means connected with said shaft for selectively movingsaid-core vertically upwardly or downwardly with respect to said outer form and for the upward movement of said shaft and core in response to an increase in the level of a mix introduced into said chamber.

2. In a packer head pipe-forming machine; a cylindrical outer form; a cylindrical inner core movable axially of said outer form to a position in spaced concentric relation to said outer form to define therewith an annular chamber for the reception of a pipe-forming mix; a shaft extending axially and outwardly from said core; means engaging said shaft for imparting axial rotation to said shaft and to said core and providing for longitudinal movement of said shaft during r0- tation thereof a packer shoe extending radially outwardly from said core for compacting a mix received in said chamber longitudinally thereof during rotation ofsaid core, said shoe being arranged to slide over the outer surface of a mix introduced into said chamber and to move said core axially of said outer form in response to an increase in the amount of mix introduced within said chamber; a fluid-pressure-responsive ram connected with said shaft and having opposed pressure areas operable in response to fluid preswhich may be employed in practicing the present invention will be readily understood. A particular feature of the present invention resides, it will be noted, in applying a determinable downward force on the fresh cementitious mix, as the latter is introduced into the mold, whereby to produce desired compaction of the mix forming concrete pipe or the like therefrom which is characterized by an uniform density throughout the length thereof. Such compaction and density will be obtained even though the consistency or water content of the mix may vary with different batches. The apparatus is essentially simple, and is capable of operating efficiently over prolonged periods of usage. Various modifications may be resorted to without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. In a packer head pipe-formin machine; a vertically arranged cylindrical outer form; a cylindrical inner core arranged to move vertically and axially with respect to said outer form to a position defining with said outer form an annular pipe-forming chamber for the reception of a pipesure for moving said core in opposite directions along the axis of said outer form; and valve means communicatin with one of the pressure areas of said ram and selectively operable to prevent the exhausting of fluid from said last-named area at less than a given high pressure and thereby to yieldably resist longitudinal movement of said core and said shaft in response to an increase in the amount of mix introduced within said pipeforming chamber. a

3. In a packer head pipe-forming machine; a cylindrical outer form; a cylindrical inner core movable axially of said outer form to a position in spaced concentric relation to said outer form to define therewith an annular chamber for the reception of a pipe-forming mix; a shaft extending axially and outwardly from said core; means engaging said shaft for imparting axial rotation to said shaft and to said core and providing for longitudinal movement of said shaft during rotation thereof; a packer shoe extending'radially outwardly from said core for compaeting a mix received in said chamber longitudinally thereof during rotation of said core, said shoe being arranged to slide over the outer surface of a mix introduced into said chamber and to move said core axially of said outer form in response to an increase in the amount of mix introduced within said chamber; a fluid-pressure-responsive ram connected with said shaft and having opposed pressure areas operable in response to fluid pressure for moving said core n opposite directions along the axis of said 7 outer form; valve means communicating with one of the pressure areas of said ram and selectively operable to prevent the exhausting of fluid from said last-named area at less than a given high pressure and thereby to yieldably resist longitudinal movement of said core and said shaft in response to an increase in the amount of mix introduced within said pipeforming chamber; and means connected with said valve means for adjusting the pressure at which fluid may be exhausted from said lastnamed pressure area.

4. Apparatus for forming concrete pipe sections comprising an, outer form member provided with a vertically arranged open-top cylindrical chamber; a cylindrical inner core of lesser diameter than the chamber of said outer form, member and arranged to move axially into and.

out of said outer form member, said inner core, when occupying a position within said outer form member, defining therewith an annular pipe-forming chamber for the reception of a cementitious mix; a shaft extending axially and upwardly from one end of said core; motordriven means connected with said shaft for imparting axial rotational movement to said shaft and to said core, said means providing for longitudinal movement of said shaft and said core during rotation thereof; a packer shoe carried on and extending radially outwardly from said core and arranged to compact a mix introduced within said pipe-forming chamber downwardly therein upon rotation of said core, said shoe being engageable with the upper level of the mix introduced into said pipe-forming chamber and being movable with said core upwardly in said chamber in response to an increase in the level of a mix introduced into said chamber; and fiuid -pressure-responsive means connected with said shaft and selectively operable to freely move said core vertically upwardly or downwardly with respect to said outer form member or to exert a predetermined pressure upon said core and said shoe to yieldably resist upward. movement thereof in response to an increase in the level of mix introduced within said pipe-forming chamber and thereby to exert compacting pressures through said shoe and against the upper level of the mix.

HECTOR X. ESCHENBRENNER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 811,297 Kielberg Jan. 30, 1906 1,047,419 Laage Dec. 17, 1912 1,144,863 Poulson June 29, 1915 1,629,922 Martin May 24, 1927 2,267,508 Spengler Dec. 23, 1941 2,497,174 Lee et a1. Feb. 14, 1950 FOREIGN PATENTS Number Country Date 2,085 Australia May 29, 1926 

